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Investment in PersolKelly Asia Pacific (Details) $ in Millions	Jul. 29, 2019 USD ($)	Jun. 30, 2019 USD ($) country	Dec. 30, 2018 USD ($)
Schedule of Equity Method Investments [Line Items]
Investment in equity affiliate		$ 122.0	$ 121.3
Accounts payable and accrued liabilities		$ 513.7	540.6
PersolKelly Asia Pacific
Schedule of Equity Method Investments [Line Items]
Equity method investment, ownership percentage		49.00%
Number of countries in which entity operates (country) (more than) \| country		10
Due from PersolKelly Asia Pacific		$ 6.4	10.2
Advances to PersolKelly Asia Pacific		7.0	7.0
PersolKelly Asia Pacific
Schedule of Equity Method Investments [Line Items]
Accounts payable and accrued liabilities		$ 0.0	$ 0.2
Subsequent Event \| PersolKelly Asia Pacific
Schedule of Equity Method Investments [Line Items]
Advances to PersolKelly Asia Pacific	$ 4.4